Yep.
Yep.
If someone really, really wants to get rid of old caps, he could just take them to the local range and put them on a table with a "FREE CAPS" sign. They would go pretty fast.
I just can't see throwing them away.
Really, really old caps, like the very earliest ones and the cheaper ones from later in the 19th century, were not waterproof and could be ruined by wetting. If you had some that old that had gotten wet, they might not be good. However, at some point, ammunition makers learned to waterproof percussion caps and the tins would have "Waterproof" or even "Double Waterproofed" someplace on the label. Those ought to still be shootable. They might be corrosive, but we clean our guns after shooting anyway.
I've been shooting some 55-year-old Alcan caps that were as good as new, and likely better than some of what's being produced now.
@Rudyard and some of the other international forum members reported shooting some very old caps with good results. If the caps which are the subject of this thread were made any time in the last century, chances are they will still detonate.
If I were determined to get rid of them, I would find a new home for them. They are too valuable to waste, especially in this time of recurrent shortages.
Just one old duffer's opinion, respectfully submitted.
Notchy Bob